1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3 * Performance event support - PPC 8xx
4 *
5 * Copyright 2016 Christophe Leroy, CS Systemes d'Information
6 */
7
8 #include <linux/kernel.h>
9 #include <linux/sched.h>
10 #include <linux/perf_event.h>
11 #include <linux/percpu.h>
12 #include <linux/hardirq.h>
13 #include <asm/pmc.h>
14 #include <asm/machdep.h>
15 #include <asm/firmware.h>
16 #include <asm/ptrace.h>
17 #include <asm/code-patching.h>
18 #include <asm/inst.h>
19
20 #define PERF_8xx_ID_CPU_CYCLES 1
21 #define PERF_8xx_ID_HW_INSTRUCTIONS 2
22 #define PERF_8xx_ID_ITLB_LOAD_MISS 3
23 #define PERF_8xx_ID_DTLB_LOAD_MISS 4
24
25 #define C(x) PERF_COUNT_HW_CACHE_##x
26 #define DTLB_LOAD_MISS (C(DTLB) | (C(OP_READ) << 8) | (C(RESULT_MISS) << 16))
27 #define ITLB_LOAD_MISS (C(ITLB) | (C(OP_READ) << 8) | (C(RESULT_MISS) << 16))
28
29 extern unsigned long itlb_miss_counter, dtlb_miss_counter;
30 extern atomic_t instruction_counter;
31
32 static atomic_t insn_ctr_ref;
33 static atomic_t itlb_miss_ref;
34 static atomic_t dtlb_miss_ref;
35
36 static s64 get_insn_ctr(void)
37 {
38 int ctr;
39 unsigned long counta;
40
41 do {
42 ctr = atomic_read(&instruction_counter);
43 counta = mfspr(SPRN_COUNTA);
44 } while (ctr != atomic_read(&instruction_counter));
45
46 return ((s64)ctr << 16) | (counta >> 16);
47 }
48
49 static int event_type(struct perf_event *event)
50 {
51 switch (event->attr.type) {
52 case PERF_TYPE_HARDWARE:
53 if (event->attr.config == PERF_COUNT_HW_CPU_CYCLES)
54 return PERF_8xx_ID_CPU_CYCLES;
55 if (event->attr.config == PERF_COUNT_HW_INSTRUCTIONS)
56 return PERF_8xx_ID_HW_INSTRUCTIONS;
57 break;
58 case PERF_TYPE_HW_CACHE:
59 if (event->attr.config == ITLB_LOAD_MISS)
60 return PERF_8xx_ID_ITLB_LOAD_MISS;
61 if (event->attr.config == DTLB_LOAD_MISS)
62 return PERF_8xx_ID_DTLB_LOAD_MISS;
63 break;
64 case PERF_TYPE_RAW:
65 break;
66 default:
67 return -ENOENT;
68 }
69 return -EOPNOTSUPP;
70 }
71
72 static int mpc8xx_pmu_event_init(struct perf_event *event)
73 {
74 int type = event_type(event);
75
76 if (type < 0)
77 return type;
78 return 0;
79 }
80
81 static int mpc8xx_pmu_add(struct perf_event *event, int flags)
82 {
83 int type = event_type(event);
84 s64 val = 0;
85
86 if (type < 0)
87 return type;
88
89 switch (type) {
90 case PERF_8xx_ID_CPU_CYCLES:
91 val = get_tb();
92 break;
93 case PERF_8xx_ID_HW_INSTRUCTIONS:
94 if (atomic_inc_return(&insn_ctr_ref) == 1)
95 mtspr(SPRN_ICTRL, 0xc0080007);
96 val = get_insn_ctr();
97 break;
98 case PERF_8xx_ID_ITLB_LOAD_MISS:
99 if (atomic_inc_return(&itlb_miss_ref) == 1) {
100 unsigned long target = patch_site_addr(&patch__itlbmiss_perf);
101
102 patch_branch_site(&patch__itlbmiss_exit_1, target, 0);
103 }
104 val = itlb_miss_counter;
105 break;
106 case PERF_8xx_ID_DTLB_LOAD_MISS:
107 if (atomic_inc_return(&dtlb_miss_ref) == 1) {
108 unsigned long target = patch_site_addr(&patch__dtlbmiss_perf);
109
110 patch_branch_site(&patch__dtlbmiss_exit_1, target, 0);
111 }
112 val = dtlb_miss_counter;
113 break;
114 }
115 local64_set(&event->hw.prev_count, val);
116 return 0;
117 }
118
119 static void mpc8xx_pmu_read(struct perf_event *event)
120 {
121 int type = event_type(event);
122 s64 prev, val = 0, delta = 0;
123
124 if (type < 0)
125 return;
126
127 do {
128 prev = local64_read(&event->hw.prev_count);
129 switch (type) {
130 case PERF_8xx_ID_CPU_CYCLES:
131 val = get_tb();
132 delta = 16 * (val - prev);
133 break;
134 case PERF_8xx_ID_HW_INSTRUCTIONS:
135 val = get_insn_ctr();
136 delta = prev - val;
137 if (delta < 0)
138 delta += 0x1000000000000LL;
139 break;
140 case PERF_8xx_ID_ITLB_LOAD_MISS:
141 val = itlb_miss_counter;
142 delta = (s64)((s32)val - (s32)prev);
143 break;
144 case PERF_8xx_ID_DTLB_LOAD_MISS:
145 val = dtlb_miss_counter;
146 delta = (s64)((s32)val - (s32)prev);
147 break;
148 }
149 } while (local64_cmpxchg(&event->hw.prev_count, prev, val) != prev);
150
151 local64_add(delta, &event->count);
152 }
153
154 static void mpc8xx_pmu_del(struct perf_event *event, int flags)
155 {
156 ppc_inst_t insn = ppc_inst(PPC_RAW_MFSPR(10, SPRN_SPRG_SCRATCH2));
157
158 mpc8xx_pmu_read(event);
159
160 /* If it was the last user, stop counting to avoid useless overhead */
161 switch (event_type(event)) {
162 case PERF_8xx_ID_CPU_CYCLES:
163 break;
164 case PERF_8xx_ID_HW_INSTRUCTIONS:
165 if (atomic_dec_return(&insn_ctr_ref) == 0)
166 mtspr(SPRN_ICTRL, 7);
167 break;
168 case PERF_8xx_ID_ITLB_LOAD_MISS:
169 if (atomic_dec_return(&itlb_miss_ref) == 0)
170 patch_instruction_site(&patch__itlbmiss_exit_1, insn);
171 break;
172 case PERF_8xx_ID_DTLB_LOAD_MISS:
173 if (atomic_dec_return(&dtlb_miss_ref) == 0)
174 patch_instruction_site(&patch__dtlbmiss_exit_1, insn);
175 break;
176 }
177 }
178
179 static struct pmu mpc8xx_pmu = {
180 .event_init = mpc8xx_pmu_event_init,
181 .add = mpc8xx_pmu_add,
182 .del = mpc8xx_pmu_del,
183 .read = mpc8xx_pmu_read,
184 .capabilities = PERF_PMU_CAP_NO_INTERRUPT |
185 PERF_PMU_CAP_NO_NMI,
186 };
187
188 static int init_mpc8xx_pmu(void)
189 {
190 mtspr(SPRN_ICTRL, 7);
191 mtspr(SPRN_CMPA, 0);
192 mtspr(SPRN_COUNTA, 0xffff);
193
194 return perf_pmu_register(&mpc8xx_pmu, "cpu", PERF_TYPE_RAW);
195 }
196
197 early_initcall(init_mpc8xx_pmu);
198
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